Page #: Page 1 of 7 Last Reviewed/Update Date: 5/18/11 Pressure Vessels 1. Purpose / Background This document describes the procedures the Massachusetts Institute of Technology (MIT) follows to ensure proper use and maintenance of pressure vessels. These procedures are intended to support MIT s Environment, Health & Safety Policy and comprise a portion of the MIT Environment, Health, and Safety Management System (EHS-MS). As defined under the EHS-MS PI Space Registration system, a pressure vessel is defined as containing a volume more than 120 gallons of water under pressure, having internal or external pressure in excess of 15 psi (pounds per square inch), and an inside diameter of more than 6 inches. Pressure vessels represent a risk for explosion and physical injury if not properly maintained. The American Society of Mechanical Engineers (ASME) outlines construction specifications for various types of pressure vessels. The Massachusetts Department of Public Safety regulates the installation of boilers, air tanks, and other pressure vessel installations. The Massachusetts Department of Public Safety regulates air tanks with a capacity of one cubic foot or more (7.48 US gallons/28.3 liters) at a pressure of 50 psi or greater. 2. Scope This SOP describes requirements and practices for pre-fabricated, custom built, or home-crafted pressure vessels that are installed and operated in laboratories and other spaces on the MIT campus. Pressure vessels, as defined by this SOP include: a) boilers; b) air tanks; c) vacuum systems and lines; d) refrigeration and air conditioning components (i.e., compressors); and e) autoclaves. Compressed gas cylinders are addressed in the SOP Compressed Gases (EHS-001). 3. Prerequisites None. 4. Management Standards 4.1. General Requirements 4.1.1 No person shall operate or use, or permit to be operated or used, an autoclave, boiler or regulated pressure vessel unless it has been inspected by a qualified inspector and a certificate of inspection has been issued, and the operator has been trained and qualified. In addition to regulatory fines resulting from unapproved installations, MIT s Property Insurer may refuse to honor damage claims resulting from inappropriately installed or operated pressure vessels. 4.1.2 Pressure vessel inspections for licensing purposes are to be inspected by certified professionals per the National Board of Boiler and Pressure Vessel Inspectors. The Board maintains a list of agencies who may be commissioned to perform boiler and pressure vessel inspections and employ individuals who have been certified by the board. 4.1.3 MIT has approximately 60 pressure vessels, i.e., research pressure vessels, which do not include boilers and pressure vessels for heating systems maintained through the Department of Facilities. The EHS Office maintains a list of research pressure vessels; MIT s Property Insurer maintains a list of boilers and heating systems which are inspected on a routine basis.
Page #: Page 2 of 7 Last Reviewed/Update Date: 5/18/11 4.1.4 All pressure vessels shall be inspected for insurance and safety purposes after installation, at prescribed frequencies, and after any welding, alterations, repair or relocation. The pressure vessel inspection application may be downloaded from: http://www.mass.gov/eeops/docs/dps/appl/appl_eng_boiler_airtank_inspection.pdf. 4.1.5 DLCs shall review design plans with the Safety Program within the Environment, Health and Safety (EHS) Office and the Department of Facilities prior to building pressure vessels for a research project. 4.1.6 The owner of a new or existing pressure vessel is responsible for maintaining the pressure vessel in accordance with the manufacturer s instructions and the requirements of the Commonwealth of Massachusetts Department of Public Safety, which incorporates by reference the ASME Boiler and Pressure Vessel Code. An unofficial copy of the regulations is available at: http://www.mass.gov/eeops/docs/dps/inf/522_cmr_1.00_14.00_board_of_boiler_rules.pdf. The ASME Boiler and Pressure Vessel Code may be purchased from: http://www.asme.org/codes/international_boiler_pressure.cfm. The sections pertaining to pressure vessels are: Section VIII, Division 1; Section VIII, Division 2 (alternative standards for owner design-specification and operated pressure vessels; and Section VIII, Division 3 (high pressure vessels exceeding 10,000 psi). 4.1.7 Persons operating autoclaves and other pressure vessels shall be trained in safe operating procedures, through Lab Specific Chemical Hygiene training or similar methods. 4.1.8 All devices meeting the definition of pressure vessel identified above shall be recorded in the PI Space Registration system. EHS Representatives are responsible for entering information into the PI Space Registration system; EHS Coordinators and EHS Lead Contacts help verify accuracy and assist EHS Representatives as needed. 4.1.9 No person shall operate an autoclave, boiler or pressure vessel at a pressure higher than its maximum allowable working pressure (MAWP). 4.1.10 Pressure vessels shall be rated to no less than 4 times the MAWP. 4.1.11 Pressure sources shall be limited to the MAWP of the lowest rated system component by a regulator and relief device (valve or disk) downstream of the regulator. 4.1.12 Every autoclave, boiler and pressure vessel shall have at least one safety or other equivalent fitting to relieve pressure at or below the vessel s maximum allowable working pressure. No pressure vessel shall be operated without an appropriate and properly functioning pressure gauge and safety relief. 4.1.13 The National Board of Boilers and Pressure Vessel Inspectors maintains an online guide to pressure relief devices, which is updated monthly. The guide may be downloaded from: http://www.nationalboard.org/index.aspx?pageid=8&id=64. 4.1.14 Gauges shall be graduated to the MAWP (but preferable 20%-30% above MAWP). Materials shall be compatible with the fluid. 4.1.15 The design function of any safety relief valve shall not be restricted by tie downs, paint, block, cap, removal, or any other means. 4.1.16 Safety relief valves shall be tested monthly while pressure vessels are in service. Where they exist, condensate valves shall be drained regularly, daily if necessary. 4.1.17 Rupture disks, where used, shall be ASME approved. Beginning January 1, 1999, rupture disks approved by ASME are marked with the UD stamp. Pressure vessels installed/constructed after January 1, 1999 that employ rupture disks must bear this UD stamp. 4.1.18 Pressure control or any other switches which control pressure shall not be bypassed. 4.1.19 Nonflexible metal pipe, tubing, fittings, and valves appropriate for the system fluid and rated at or above the system MAWP shall be used. Special flexible metal hose shall be used where flexing is required.
Page #: Page 3 of 7 Last Reviewed/Update Date: 5/18/11 4.1.20 Autoclaves, boilers, and pressure vessels shall be maintained and repaired by qualified persons. Departments, Labs, and Centers (DLCs) are responsible for maintaining autoclaves and other pressure vessels. 4.1.21 Where, in the course of such maintenance and repairs, an employee is required to enter a boiler or pressure vessel, the employee shall have received, and comply with, Confined Space training. Refer to Training for additional information. 4.1.22 Pressure vessels shall be kept mounted level at all times with vibration protection in place. Do not mount the vessel rigidly without vibration buffer supports under tank legs. 4.1.23 All components should be secured to a firm foundation; hose and tubing should be firmly supported, with the end secured to prevent whipping in the event a connection fails. Adequate machine screws or bolts should be used to secure all components. 4.1.24 Pressure vessels shall be protected from damage caused by vehicle traffic or general plant or lab operations. Materials, supplies, or other stock shall not be piled up against the vessel. 4.1.25 All welded repairs shall be made only by companies holding the R stamp authorization or the ASME U symbol; these are certificates that ASME issues to the company. ASME grants the R certificate for repair or alteration of equipment to the National Board of Boiler and Pressure Vessel Inspectors Code, and grants the U Certificate for Construction of Pressure Vessels to the ASME Code. If a researcher in a DLC wishes to have a welded repair performed on a pressure vessel, that individual shall request from the company either a copy of the certificate or a certificate number. 4.1.26 The decommissioning of autoclaves, boilers and pressure vessels shall also be reported to the EHS Office. Refer to the SOPs Moving a Laboratory: Preparation and Decontamination (EHS-0026) and Deactivating and Decommissioning Equipment (EHS-0049) for additional information. Certificates must be turned in for pressure vessels that are no longer operational. 4.2. Inspection Certificates Process and Requirements 4.2.1 Inspection certificates issued by the Department of Public Safety shall be posted in a conspicuous place near the autoclave, boiler, or pressure vessel. 4.2.2 With information from the EHS Representatives, the EHS Office shall complete the Massachusetts Department of Public Safety s Inspection Application Pressure Vessel Data. The inspection for new installations shall be an internal and external exam of the system. 4.2.3 Re-inspections may be conducted by either a licensed inspector from the Massachusetts Department of Public Safety or a licensed inspector from MIT s Property Insurance carrier. 4.2.4 Re-inspections shall be conducted every 2 years. 4.2.5 Copies of the application for inspection form may be downloaded from: http://www.mass.gov/eeops/docs/dps/appl/appl_eng_boiler_airtank_inspection.pdf. 4.2.6 The DLC shall provide the EHS Office with a $50.00 payment for each pressure vessel to be inspected and licensed. The individual PI is responsible for this payment. 4.2.7 The Safety Program shall notify the DLC when the Inspector has checked the pressure vessel and has issued a certificate. 4.2.8 The DLC shall provide the Safety Program with a requisition for a plaque that is embossed with the following information: Certificate of Inspection is on file in the Environment, Health, and N52-496 tel: 452-3477 Dept:
Page #: Page 4 of 7 Last Reviewed/Update Date: 5/18/11 These plaques take the place of posting the renewed certificates of inspection every two years. Copies of the certificates are available upon request. If the pressure vessel is portable, EHS recommends chaining the plaque to the equipment. The Department of Facilities stockroom (E19-111) sells 1/8 inch and S hooks that fit the pre-drilled holes in the plaques. If the pressure vessel is stationary, use the mounting squares to attach the plaque to a nearby wall. EHS recommends also using wall screws if oil mist or steam is present. 4.2.9 The DLC shall notify the Safety Program in the event the equipment is moved to another lab. Space registration for the PI s lab space shall be revised accordingly. 4.2.10 The DLC shall notify the Safety Program when the equipment will be disposed, in order to allow EHS to return the inspection certificate. 4.3. Air Tanks 4.3.1 Connecting to the building compressed air system is generally preferable to a new air tank installation. DLCs shall contact the Department of Facilities (HVAC Systems Team) regarding connecting to the building s compressed air system instead of buying a new air tank. 4.3.2 If connecting to the building air system is not possible and a new installation is required, then the DLC must verify that the air tank/ pressure vessel is built to ASME standards and has a code stamp on it. 4.3.3 The Massachusetts Code requires that owners install new air tanks with 12 inches between the tank and the floor, wall or other obstruction. 4.3.4 Locate the air tank so the condensate can be drained once a week or install an automatic drain valve. 4.3.5 Locate the safety valve so it can be easily tested once a month. 4.3.6 Inspect the tank at least weekly for air leaks. If an air leak is found, determine its source (i.e. line, fitting or crack). 4.3.7 Do not make welded repair on air tanks. 4.3.8 Do not use plastic pipe for any air discharge line. 4.3.9 When designing a compressed air system for a building/ large area, a second air receiver for each system is needed to allow for uninterruptible service during maintenance and inspections. The system valve arrangement shall be in a manner that allows switching between air receivers. 5. Roles & Responsibilities 5.1. Principal Investigator/Pressure vessel operators shall: 5.1.1 Work with the Department s EHS Coordinator, EHS Office, and the Department of Facilities to ensure pressure vessel installations meet ASME code, are properly permitted, and leverage existing building infrastructure (e.g., building compressed air, central compressed gas distribution systems); 5.1.2 Operate systems in accordance with the criteria in Sections 4.1 and 4.3 of this SOP; 5.1.3 Inspect safety and pressure relief systems at least monthly while the pressure vessels are in service; 5.1.4 Where they exist, ensure that condensate lines are drained at least weekly; 5.1.5 Routinely inspect the system for signs of wear, and have the system repaired by a licensed contractor if repairs are required;
Page #: Page 5 of 7 Last Reviewed/Update Date: 5/18/11 5.1.6 Develop standard operating procedures for the pressure vessel, including warning signs and emergency shutdown; and 5.1.7 Assist the EHS representative in communicating safe practices to those working in the vicinity of the pressure vessel. 5.1.8 Provide the $50.00 inspection fee to MIT EHS/Inspector to accompany the license application. 5.2. EHS representatives, as delegated by the Principal Investigators, shall: 5.2.1 indicate whether pressure vessels are present in the PI Space Registration system; 5.2.2 ensure that personnel working with pressure vessels have developed SOPs for their safe operation; 5.2.3 include safety procedures for pressure vessels as part of annual laboratory specific chemical hygiene training or hazard communication training; and 5.2.4 Work with the pressure vessel operator to ensure licenses, where they are required, are obtained for pressure vessels. This includes making arrangements to be present for bi-annual pressure vessel licensing inspections. 5.3. EHS Coordinators shall: 5.3.1 Ensure individuals who are performing work on/in pressure vessels designated as confined spaces have received appropriate training; 5.3.2 Ensure PI spaces are accurately registered for the presence of pressure vessels; 5.3.3 Work with the EHS Office to coordinate the decommissioning of pressure vessels; 5.3.4 ensure pressure vessel plaques and licenses are appropriately displayed; and 5.3.5 Assist the EHS Office with walkthroughs of spaces with pressure vessels for insurance and/or state licensing purposes. 5.4. EHS Office shall: 5.4.1 Maintain a master list of licensed pressure vessels on campus and ensure applications for inspection are submitted on the required 2-year cycle; 5.4.2 Work with EHS Coordinators to ensure that licenses for decommissioned pressure vessels are turned in and the pressure vessel removed from PI Space Registration and the Research Pressure Vessel master list; 5.4.3 Review pressure vessel design information with the operator, coordinate with the Department of Facilities on EHS issues related to installation of pressure vessels (e.g., toxic gas monitoring, fire protection need, etc.) along with any supplemental EHS training that may be required (e.g., hydrofluoric acid safety, confined space entry); 5.4.4 Ensure emergency response procedures for major/high hazard pressure vessel installations have been developed and disseminated to emergency response personnel and affected DLCs; and 5.4.5 Accompany insurance and state agency inspectors on walkthroughs of campus spaces where pressure vessels are operated. 5.4.6 Provide MIT s Insurance Carrier with an updated list of research vessels to be included as part of its boiler inspection master list. 5.5. Department of Facilities shall: 5.5.1 Ensure boiler installations have been installed per code and are operated by a licensed professional; and 5.5.2 Provide guidance to DLCs on the availability of building air systems.
Page #: Page 6 of 7 Last Reviewed/Update Date: 5/18/11 6. Training 6.1. Procedures for safe operation and emergency shutdown of pressure vessels shall be included as part of annual laboratory-specific chemical hygiene training, or hazard communication training for non-laboratory areas. 6.2. Individuals who may be required to perform maintenance, including clean-outs, of pressure vessels could be subject to confined space training requirements. Individuals working around a designated confines space can register for course EHS0444c-A: Confined Space Awareness. Individuals who will be servicing confined areas can register for course EHS0430c-A: Confined Space Entrant/Attendant. Training registration is at http://web.mit.edu/sapwebss/ps1/training_home.shtml. 7. Monitoring Requirements 7.3. Tanks shall be drained of condensate at least weekly. If your tank creates large amounts of condensate, contact Department of Facilities Mechanical Operations to install an automatic drain valve. 7.4. Safety valves shall be tested monthly, and replaced when necessary. The Department of Facilities stockroom (x3-4752) may be contacted to determine if the valve to be replaced is in stock or to order one. 7.5. DLCs shall maintain logs of routine pressure vessel component testing and maintenance/service activities. 8. Record Management Inspection and training records shall be retained in accordance with the SOP Records Retention, EHS Office (EHS-0021). 9. References 9.1. Standards 9.1.1. 522 CMR 100-17.00 Massachusetts Division of Public Safety, Board of Boiler Rules 9.1.2. ASME Boiler and Pressure Vessel Code 9.1.3. OSHA 1910.169, Air Receivers 9.2. Other SOP/ SOGs 9.2.1 Compressed Gases (EHS-001) 9.2.2 Deactivating and Decommissioning Equipment (EHS-0049) 9.2.3 Moving a Laboratory: Preparation and Decontamination (EHS-0026) 9.2.4 Records Retention, EHS Office (EHS-0021) 9.3. Supplementary Documents 9.3.1. MIT Spill Prevention, Control, and Countermeasures (SPCC) plan 9.3.2. National Safety Council (NSC) Data Sheet: 1-678-Rev-85: Pressure Vessels and Pressure Systems in the Research and Development Lab.
Page #: Page 7 of 7 Last Reviewed/Update Date: 5/18/11 10. Definitions 10.1. ANSI the American National Standards Institute. ANSI is a non-profit organization that works with the public and private sector to develop voluntary, uniform testing and performance requirements for materials, products, and systems. 10.2. ASME the American Society of Mechanical Engineers. 10.3. Autoclave - a sterilizer for liquids and materials that uses high pressure steam, and designed to produce and withstand high pressures and high temperatures. Sterilization is accomplished through timed exposure of liquids or materials to high pressure and high temperatures such that all viable microorganisms in the liquids/materials within the chamber are killed. 10.4. Boiler - a fired vessel in which gas or vapor may be generated or a gas vapor or liquid may be put under pressure by heating and includes any pipe, fitting or other equipment attached to or used in connection with the vessel. 10.5. PSI pounds per square inch, a standard unit to measure pressure. 10.6. Pressure - force applied to or distributed over a surface, measured above the prevailing atmospheric pressure, e.g. kilopascals or pounds per square inch (psi). 10.7. Pressure vessel - an unfired vessel that may be used for containing, storing, distributing, transferring, distilling, or processing any gas, vapor or liquid under pressure, and includes any pipe, fitting and other equipment attached to or used in connection with the vessel. Vessels containing a volume more than 120 gallons of water under pressure, having internal or external pressure in excess of 15 psi, and an inside diameter of more than 6 inches. 10.8. Qualified person - a person who, in respect of a specified duty, is qualified by knowledge, training and experienced to perform the duty safely and properly.